Extension arm

ABSTRACT

The invention relates to an extension arm ( 1 ), especially a pivotal and adjustable-tilt extension arm for a supporting system, for the suspending fixing of preferably medial devices ( 2 - 5 ) by means of a joining element ( 6 - 9 ) fastened to a fixing piece ( 17 ) of the extension arm ( 1 ). Said extension arm comprises a securing element ( 34 ), which is guided through an opening ( 35 ) of the fixing piece ( 17 ) and secures the fastening of the joining element ( 6 - 9 ) to the fixing piece ( 17 ) by engaging inside a groove ( 36 ) of the joining element ( 6 - 9 ). The extension arm also comprises a securing bush ( 26 ), which at least partially surrounds the fixing piece ( 17 ) and the joining element ( 69 )and which secures the securing element ( 34 ). To this end, a spring element ( 40 ) is provided, which is at least partially supported on the securing bush ( 26 ) in order to hold the securing element ( 34 ) in the groove ( 36 ) of the joining element ( 6 - 9 ) using pretension force.

[0001] The invention relates to an extension arm, particularly apivotable and inclinable extension arm, for a supporting system, for thesuspended attachment of preferably medical devices.

[0002] A known extension arm comprises a horizontal or spring arm, whichis attached by means of a connecting piece of the extension arm to aceiling mount which is preferably mounted on the ceiling of a room inwhich the devices are used. Here, the connecting piece is connected tothe horizontal arm by way of a hinge joint, so that the horizontal armcan be inclined relative to the connecting piece with respect to thehorizontal. Moreover, the extension arm has an attachment piece which isconnected by means of a joint piece to the horizontal arm and on whichfor example medical equipment, such as an operating light or aprotective X-ray shield may be attached. In order to enable a pluralityof different devices to be attached to the extension arm, the connectionis designed to be releasable, which means that it is necessary to securethe connection in order to prevent the connection from being releasedunintentionally. The known securing means has a securing element whichengages in a groove in the connecting element connected to the device,thus blocking withdrawal of the connecting element from the attachmentpiece. Here, the connection is designed in such a way that part of theweight of the device acts on the securing element in the assembledcondition.

[0003] The known extension arm has a plurality of disadvantages. In thecourse of time, the securing element can escape from the groove with theresult that it now engages only partially in the groove and the securingforce is considerably reduced in the event of maloperation. If thesecuring element engages only partially in the groove, the problemmoreover arises that—if the device to be attached is very heavy—the loadfrom only part of the weight of the device is sufficient to bend thesecuring element or damage the connecting element in the region of thegroove as a result of the load on the securing element in the region ofthe groove in the connecting element. During dismantling, e.g.dismantling for the purpose of attaching another medical device, thiscan also result in it no longer being possible to remove the securingelement from the groove in the connecting element—or it only beingpossible to remove it with difficulty—with the result that substantialrepair measures are required. There is moreover a risk of the securingelement not engaging evenly in the groove in the connecting element,with the result that the securing force is relatively small and theproblems discussed above arise accordingly.

[0004] The object of the invention, therefore, is to provide anextension arm in which the functionability of the securing mechanism isensured and, in particular, the cooperation between the securing elementand the connecting element is improved, and furthermore to devise aprocess by means of which this secure connection can be produced.

[0005] The object is achieved by an extension arm having the features ofclaim 1 and by a process having the features of claim 11.

[0006] The extension arm according to the invention is advantageous inthat the securing element for securing the attachment of the connectingelement on the attachment piece is held in the groove of the connectingelement by the spring element, thus achieving a reliable securing actionwhereby the securing element is prevented from escaping from the groovein the connecting element and an uneven load on the securing element inthe region of the groove is avoided, with the result that the extensionarm is more secure and is particularly suitable for relatively greatweights, i.e. for heavy devices, acting on the attachment piece.

[0007] Advantageous further developments of the extension arm describedin claim 1 are possible as a result of the features described in claims2 to 10.

[0008] At least one securing screw is advantageously provided, which isscrewed into the securing bush and on which the spring element is atleast partially supported. Thus, the pre-tension force of the springelement can be adjusted and particularly additionally increased, thesecuring screw additionally being acted upon by a spring force from thespring element, so that the securing element is additionally preventedfrom being released unintentionally.

[0009] It is advantageous that the securing screw cooperates with thesecuring element to block a displacement of the securing bush relativeto the securing element. This prevents the securing bush from beingdisplaced with respect to the attachment piece in such a way that thesecuring element and/or further securing or attachment means, e.g. acylinder pin, are not secured.

[0010] It is advantageous that the securing bush has a cutout in whichthe securing element and the spring element are partially arranged.Thus, the position of the securing element and/or the position of thespring element can be additionally fixed, so that in particular tiltingof the securing element or the spring element in a plane perpendicularto the axis of the attachment piece is prevented.

[0011] The spring element is advantageously constructed from apreferably metal spring strip. It is advantageous here that the springelement has a first portion and a second portion which, in a relaxedcondition of the spring element, are arranged at least substantiallyperpendicular to one another. This results in a spring element which iseasy to manufacture and which generates a large spring force in theassembled condition of the extension arm.

[0012] It is furthermore advantageous that the first portion is longerthan the second portion. Thus, the spring element can be advantageouslyguided in between the securing bush and the securing element and alignedbetween them. Advantageous alignment of the spring element in the cutoutin the securing bush is particularly possible.

[0013] It is advantageous that the second portion is constructed to besuch a length that it projects at least approximately over the loweredge of the securing bush in the assembled condition of the extensionarm. Thus, when assembling the extension arm, it is particularly easy todetermine whether the spring element is assembled correctly. Thismoreover enables the assembly personnel to carry out a simple check asto whether the spring element is installed in order to ensure thesecurity of the extension arm. An essential factor here is that it isnot necessary to carry out dismantling procedures in order to checkwhether the spring element is installed and whether it has been arrangedcorrectly; instead this is possible merely by means of externalexamination.

[0014] The first portion and the second portion are advantageouslyconnected by means of a U-shaped middle portion which abuts at leastpartially against the securing element. Thus, the assembled position ofthe spring element is fixed in a direction parallel to the axis of theattachment piece, thus further simplifying assembly.

[0015] It is furthermore advantageous that at least one securing screwis provided, which is screwed into the securing bush and engages atleast partially in the U-shaped middle portion of the spring element.Thus, the spring element is additionally secured, the securing bushmoreover being secured against displacement in a direction along theaxis of the attachment piece.

[0016] The inventive process according to claim 11 is advantageous inthat the securing element is pushed particularly deep into the groove inthe connecting element in that the securing spring is pushed in betweenthe securing bush and the securing element, the securing elementadditionally being acted upon by a holding force in that the securingspring is pre-tensioned by means of the securing bush as a result ofdisplacing this latter along the attachment piece.

[0017] Advantageous further developments of the process described inclaim 11 are possible as a result of the measures described in claims 12and 13.

[0018] It is advantageous that a securing screw is furthermore screwedinto the securing bush in order to block displacement of the securingbush and additionally tension the securing spring.

[0019] It is moreover advantageous that the connecting means connectingthe connecting element to the attachment piece is inserted through anopening in the securing bush.

[0020] Exemplary embodiments of the invention are illustrated insimplified manner in the drawing and explained in more detail in thedescription below. There is shown:

[0021]FIG. 1 an exemplary embodiment of an extension arm according tothe invention, with a plurality of medical devices which can beconnected to the extension arm, in a partially exploded illustration;

[0022]FIG. 2 the section denoted by II in FIG. 1;

[0023]FIG. 3 a detail of the extension arm according to the inventionduring assembly of the spring element;

[0024]FIG. 4 a detail of the extension arm according to the inventionafter assembly of the spring element; and

[0025]FIG. 5 a detail of the extension arm according to the invention inthe assembled condition, in a partially sectional illustration.

[0026]FIG. 1 shows an extension arm 1 for the suspended attachment ofdevices 2-5. For this, each of the devices 2-5 has a connecting element6-9. The extension arm 1 and the connecting elements 6-9 are componentsof a supporting system which enables the preferably medical devices,e.g. a protective X-ray shield 10 and a display screen 11 to beexchangeably suspended in a room, the devices being suspended forexample on a ceiling mount, e.g. in the form of a mounting rail, fixedto the ceiling.

[0027] The extension arm 1 has a connecting piece 12 which comprises acylindrical pin 13, the extension arm 1 being pivotable about the axisof rotation 14. Moreover, the extension arm 1 has a horizontal arm 16,which is connected to the connecting piece 12 by means of the jointpiece 15 and is pivotable or rotatable about the axis of rotation 14 ofthe pin 13 and inclinable with respect to a horizontal plane orientatedperpendicularly to the axis of rotation 14. The extension arm 1 moreoverhas an attachment piece 17 which is connected by means of a joint piece18 to the horizontal arm 16, so that the attachment piece 17 ispivotable about the axis 19 of the joint piece 18, relative to thehorizontal arm 16.

[0028] The horizontal arm 16 can be constructed as a spring arm, as aresult of which the weight of a device 2-5 is compensated and the device2-5 remains in the predetermined position.

[0029] The invention is described in more detail below, with referenceto FIG. 2 which shows the section denoted by II in FIG. 1. Elementswhich have already been described are provided with correspondingreference numerals in all figures, thus making repeated descriptionunnecessary.

[0030] For transporting the extension arm 1, the protective cap 25 isinstalled in the attachment piece 17 at the factory in order to deliverthe extension arm 1 in a condition similar to that required forattaching a device 2-5, so that, as a result of the preparatorydismantling of the extension arm 1, it becomes clear to the assemblypersonnel how the extension arm 1 is to be initially assembled duringconnection to a device 2-5. It is thus possible to prevent assemblyerrors which may arise for example as a result of misunderstanding theassembly instructions. The attachment of the device 6 or 8 to theextension arm 1 is described below. First of all, the securing bush 26is pushed onto the attachment piece 17 and then the connecting element6, 8 of the device 2, 4 is pushed into the attachment piece 17, theinsertion depth being fixed by the stop 27 which abuts against theunderside 28 of the attachment piece 17. Care should be taken here toarrange the elongated cutout 29 in the attachment pin 30 of theconnecting element 6 opposite the cutout 31 in the attachment piece 17.In a suitable first position of the securing bush 26, the connectingmeans 32, which is constructed in this exemplary embodiment as acylinder pin, can be inserted through the opening 33 in the securingbush 26 into the cutout 31, through the elongated cutout 29 in theconnecting element 6, 8 and into a cutout in the attachment piece 17,which is opposite the cutout 31. Thus, the connecting element 6, 8 isconnected to the attachment piece 17 by means of the connecting means32, as a result of which the device 2, 4 is attached to the extensionarm 1 in suspended manner.

[0031] To secure this attachment, the securing element 34 is insertedinto a groove 36 in the connecting element 6, 8 through the opening 35in the attachment piece 17 whilst the securing bush 26 is in a positionclose to the first position. The securing element 34 has a bent part 37and a nose-shaped part 38. The bent part 37 is inserted at leastpartially into the groove 36, the radius of curvature of the bent part37 of the securing element 34 being adapted to the inside radius of theperipheral groove 36. The first portion 39 of a spring element 40 isplaced over the nose-shaped part 38 of the securing element 34, a stopfor the spring element 40 against the nose 34 being produced by aU-shaped middle portion 41. After the spring element 40 has been pushedin, the securing bush 26 is displaced along the attachment piece 17 intoa second position by way of the. second portion 42 of the spring element40, the securing spring 40 being pre-tensioned in that the secondportion 42 is bent back.

[0032] In the second position of the securing bush 26, a securing screw46 is screwed into the threaded bore 45 in the securing bush 26 so that,on the one hand, the spring element 40 is at least partially supportedon the securing screw 46 and, on the other, displacement of the securingbush 26 relative to the securing element 34 or relative to theattachment piece 17 is blocked as a result of the securing screw 46engaging in the U-shaped middle portion 41 of the spring element 40. Afurther securing screw 47 is furthermore provided, which is guidedthrough a bore in the securing bush 26 and engages in a threaded bore inthe attachment piece 17 in order to additionally secure the securingbush 26, particularly against twisting with respect to the axis 48 ofthe attachment piece 17. A plastic cap 49 is provided for closing theopening 33.

[0033] As an alternative to attaching the device 2 or 4 to theattachment piece 17 by means of the connecting means 32, in the case ofthe extension arm according to the invention it is also possible toprovide other attachments which are secured accordingly.

[0034] For example, the devices 3 and 5 can be connected to theextension arm 1 in that a screw is screwed into the connecting element7, 9 through an opening corresponding to the opening 33, it beingpreferable to provide a plurality of such screws. The securing bush 26accordingly prevents the screw from being released, and the connectingmeans. 32 is also prevented from becoming displaced. It is thereforeclear that the attachment between the connecting element 6-9 and theattachment piece 17 can be secured according to the inventionirrespective of the concrete design of the attachment.

[0035] The securing bush 26 has an approximately rectangular cutout 50,the spring 40 being guided in between the securing bush 26 and theattachment piece 17 in the region of the cutout 50. During assembly, itis thus easier to recognise where the spring 40 is to be assembled.Moreover, the cutout 50 defines a lower edge 51 of the securing bush 26.The second portion 42 of the spring element 40 is constructed to be sucha length that it projects at least approximately over the lower edge 51of the securing bush 26 in the assembled condition of the extension arm1, as a result of which it is readily possible to detect from theoutside whether the spring element 40 has been mounted correctly. Thus,as a result of the cutout 50 and the correct choice of length for thesecond portion 42 of the spring element 40, it is easily possible tocheck the securing action according to the invention.

[0036]FIG. 3 shows a detail of the extension arm 1, in which thesecuring bush 26 is located in the first position.

[0037] In order to mount the securing bush 26 in the first position onthe attachment piece 17 of the extension arm 1, it has been moved alongthe attachment piece 17 in the direction 60 of the horizontal arm 16. Inthis position, the securing element 34 has been pushed through theopening 35 in the attachment piece 17 and into the groove 36 in theconnecting element 6 through the cutout 50. The nose-shaped part 38 ofthe securing element 34 is partially visible in FIG. 3. When thesecuring screw 46 is removed, the spring element 40 is pushed over thenose-shaped part 38 of the securing element 34 in between the securingbush 26 and the attachment piece 17 until the U-shaped middle portion 41abuts against the nose-shaped part 38 of the securing element 34, asshown in FIG. 4.

[0038] The second portion 42 of the spring element 40 is arrangedsubstantially perpendicularly with respect to the first portion 39, sothat the second portion 42 protrudes substantially perpendicularly fromthe attachment piece 17.

[0039] As shown in FIG. 5, the securing bush 26 is then displaced alongthe attachment piece 17 in the direction 65, which is opposite to thedirection 60, into a second position, the second portion 42 of thespring element 40 being bent to the attachment piece 17 as a result ofthe action of the lower edge 51 of the securing bush 26 in order topretension the spring element 40. In the second position shown in FIG.5, the threaded bore 45 is located on the side of the second portion 42of the spring element 40, as seen from the securing element 34.

[0040] Therefore, in this position, the securing screw 46 engages in thethreaded bore 45 in the U-shaped middle portion 41 of the spring element40 when it is screwed in, thus blocking a displacement of the securingbush 26 along the attachment piece 17 in opposition to the direction 65.Since the securing bush 26 abuts at the lower edge 66 against the stop27 of the connecting element 6, a displacement of the securing bush 26along the attachment piece 17 in the direction 65 is moreover blocked.Thus, the displacement of the securing bush 26 along the attachmentpiece 17 is blocked in both directions and a release of the securingelement 34 and, where applicable, the connecting means 32, is preventedunder all circumstances.

[0041] In order to enable the securing element 34 and the spring element40 to be received, the securing bush 26 has a cutout 67 whereof thewidth is somewhat greater than the width of the strip-shaped springelement 40, so that the spring element 40 is guided into the cutout 67upon insertion. Thus, the position of the strip-shaped spring element 40is produced by the cutout 67, and, in particular, lateral displacementof the spring element 40 is permanently reliably prevented.

[0042] The invention is not restricted to the exemplary embodimentsdescribed. In particular, the described securing means and the describedsecuring process can be used for a plurality of different attachmentoptions.

1. An extension arm (1), particularly a pivotable and inclinableextension arm for a supporting system, for the suspended attachment ofpreferably medical devices (2-5) by means of a connecting element (6-9)to an attachment piece (17) of the extension arm (1) having a securingelement (34), which is guided through an opening (35) in the attachmentpiece (17) and secures the attachment of the connecting element (6-9) onthe attachment piece (17) by engaging in a groove (36) in the connectingelement (6 9), a securing bush (26), which surrounds the attachmentpiece (17) and the connecting element (6-9) at least partially andsecures the securing element (34) and a spring element (40), which is atleast partially supported on the securing bush (26) in order to hold thesecuring element (34) in the groove (36) in the connecting element (6-9)by means of a pre-tension force:
 2. An extension arm according to claim1 characterised in that at least one securing screw is provided (46),which is screwed into the securing bush (26) and on which the springelement (40) is at least partially supported.
 3. An extension armaccording to claim 1, characterised in that the securing screw (46)cooperates with the securing element (34) to block a displacement of thesecuring bush (26) relative to the securing element (34).
 4. Anextension arm according to one of claims 1 to 3, characterised in thatthe securing bush (26) has a cutout (67) in which the securing element(34) and the spring element (40) are partially arranged.
 5. An extensionarm according to one of claims 1 to 4, characterised in that the springelement (40) is constructed from a preferably metal spring strip.
 6. Anextension arm according to claim 5, characterized in that the springelement (40) has a first portion (39) and a second portion (42) which,in a relaxed condition of the spring element (40), are preferablyarranged at least substantially perpendicular to one another.
 7. Anextension arm according to claim 6, characterised in that the firstportion (39) is longer than the second portion (42).
 8. An extension armaccording to claim 6 or 7, characterised in that the second portion (42)is constructed to be such a length that it projects at leastapproximately over a lower edge (51) of the securing bush (26) in theassembled condition of the extension arm (1).
 9. An extension armaccording to one of claims 6 to 8, characterized in that the firstportion (39) and the second portion (42) are connected by means of aU-shaped middle portion (41) which abuts at least partially against thesecuring element (34).
 10. An extension arm according to claim 9,characterised in that at least one securing screw (46) is provided,which is screwed into the securing bush (26) and engages at leastpartially in the U-shaped middle portion (41) of the spring element(40).
 11. A process for assembling a preferably medical device (2-5) bymeans of a connecting element (6-9) on an extension arm (1),particularly a pivotable and inclinable extension arm for a supportingsystem, in a suspended attached position, having the following processsteps: a) assembling a securing bush (26) on an attachment piece (17) ofthe extension arm (1) in a first position (FIGS. 3 and 4); b) pushingthe connecting element (6-9) into the attachment piece (17); c)connecting the attachment piece (17) to the connecting element (6-9) byinserting a connecting means (32), particularly a cylinder pin; d)inserting a securing element (34) into a groove (36) in the connectingelement (6-9) through an opening (35) in the attachment piece (17); e)pushing a spring element (40) at least partially in between the securingbush (26) and the securing element (34); and then f) displacing thesecuring bush (26) along the attachment piece (17) into a secondposition (FIG. 5), the spring element (40) being pre-tensioned.
 12. Aprocess according to claim 11, characterised by the step following stepf): g) screwing a securing screw (46) into the securing bush (26) inorder to block displacement of the securing bush (26) and additionallytension the spring element (40).
 13. A process according to claim 11 or12, characterised in that in step c), the connecting means (32) isinserted through an opening (33) in the securing bush (26).